Automatic transmission



Sept. 26, 1950 R. F. GREBB AUTOMATIC TRANsuIssIoN 2 Sheets-Sheet 1 Filed April 22. 1946 INVENTOR.

A TTORNE Y.

Sept. 26, 1950 R. F. GREBB 2,523,619

AUTOMATIC TRANSMISSION Filed April 22, 194e 2 sheets-sheet 2 INVENToR.

Roan? 7 E G/n' Patented Sept. 26, 1950.

UNiTEo srA'ras PATENT OFFICE] an'rom'rrc 'rinussmssloisl anbei-z r. anni, Boas, nano Application April zz. ms, serial is. 664,080

This invention relates to an automatic iluid transmission for automotive vehicles and has for its principal object the provision of a simple and highly eillcient device in which the increase or decrease of the gear ratio will be automatically controlled in accordance with the load demands without attention o n the part of the operator.

A further object of the invention is to make use of the "slip of a uid clutch as a means for regulating the gear ratio of 'a planetary transmission. Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and eillciency. These will become more apparent from the following description. v o

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a longitudinal section through the im proved fluid transmission;

Fig. 2 is a cross section therethrough taken on the line 2-2, Fig. 1; and

Figs. 3, 4, and 6 are similar cross sections taken on the lines 3`-3, 4 4, 5 5. and l-I, Fig. 1. respectively.

The improved transmission is mounted in a gear case I0 which in turn is mounted on a ily wheel housing Il. An engine shaft I2 enters the ily wheel housing II and carries a ily wheel I3 therein.

A drive shaft I4 is splined into the extremity of the engine shaft I2 so as to rotate in therewith. The drive shaft carries a drive gear IB keyed thereto which rotates in constant mesh with a rst set of planet gears II. The rst set of planet gears I6 are in constant mesh with a ring gear I1 fixedly mounted in a ring gear housing I3.

The planet gears I6 are carried on a planet gear spider I9 which is rotatably mounted on the drive shaft I4. A sun gear is formed on the hub of the planet gear spider I3 and constantly meshes with a second set of planet gears 2|.

The second set of planet gears 2| are in mesh with aA second ring gear 22 xediy mounted in the ring gear housing Ill.` The second set of planet gears 2l-are carried on a second planet gear spider 23 provided with a hub 24 which is rotatably mounted on the drive shaft I4.

The extremity of the hub 24 is splined to slidably receive a toothed shifting clutch member 2l.

4 cum.' (ci. 'i4-rss) 2 y 'Ihe clutch member 25 is slidably splined upon a driven shaft 23 which is separated from the drive shaft I4 by means o f a thrust bearing 21. The clutch member 25 can be shifted back and forth by means of a shifting yoke 23 or in any otherdesired manner. v

A clutch sleeve 23 extends from a point adjacent the ily wheel I3 to a point adjacent the drive gear I5. The sleeve 29 is freely rotatable upon the drive shaft I4. A clutch disc 30 is secured. onr one extremity of the clutch sleeve and positioned, when engaged, to x the clutch sleeve 23 to the ring gear housing I8. Theclutch is operated through the medium of a sliding springs 33.

A bladed iluid clutch rotor 34 is flxedly mounted on the other extremity of the sleeve 23 adjacent the ily wheel I3. A fluid housing 35 is mounted on and sealed to the fly wheel 3| so as to surround the rotor 34. The clutch housing 25 is maintained full of oil by means of an oil pump 3l driven from a drive gear 31 on a hub 33 formed on the housing 36 and rotatably mounted on the sleeve 20. The housing 35 is provided with internal fluid vanes 43 which cooperate with the rotor 34 to create a fluid clutch between the rotor and the ily wheel I3. l

The pump 38 forces oil throughv the sleeve 2l into the housing 35 and through suitable conventional oil channels to the other operating parts of the transmission. The oil returns toV an oil sump 3l at the bottom of the case I0.

The forward extremity of the drive shaft I4 is supported by the engine shaft I2 and the rearward extremity is supported by meansf of the hub 24 which in turn is mounted in anti-friction bearings 43 in an end plate 4I in the end of the case I0.

Three reverse gears 42 are mounted on the end plate 4I so as to be in constant mesh with gear teeth 43 on the hub 24. The reverse gears 42 are in constant mesh with a reverse ring gear 44 xed to a reversing drum 45 which is rotatably mounted on the hub 24. The drum 4E is provided with a toothed clutch hub 43 which can be engaged by the clutch member 25 when the latter is moved to the left in Fig. l. The reversing mechanism and the clutch member are enclosed in a cap 41 on the end of the case III.

peration Assuming the engine is running. This imparts a forward rotation, through the engine shaft I2 and the drive shaft I4, to the drive lgear aseaem i5. This rotation causes the first set of planet gears i6 to rotate about their individual axes using the ring gear Il as a traction gear. This causes the sun gear 20 to rotate forwardly at reduced speed. The sun gear 20 imparts a rearward rotation to the individual gears of the second set. The spider 23 is being held stationary by the stationary shaft 26. Therefore, the second set of planet gears 2i rotate the housing and the rotor 34 rearwardly due to the clutch 30 being normally engaged.

As the speed of the engine increases, the centrifugal action of the fluid in the housing 35 gradually stops the reverse rotation of the housing I8 causing the second set of planet gears to revolve forwardly about the axis of the drive shaft I4 carrying the driven shaft forward. The increased engine speed also accelerates the drive gear i which also accelerates the entire train to the driven shaft 26. Eventually a point will be reached when the rotor 34 will be rotating at the the speed of the housing 35. When this occurs, the entire mechanism within the housing i8 will rotate as a, fixed unit transmitting power to the driven shaft 26 at a one to one ratio. Should the load increase on the driven shaft, the revolutions of the second planet gears 2| around the axis of the drive gear will be retarded causing them to act against the housing i8 as a traction gear and act to increase the gear ratio automatically. This increase is communicated through the first set of planet gears so that each assumes its part of the driving ratio.

To obtain a reverse movement, the clutch member 25 is slid to the left in Fig. 1 until it disengages the teeth on the hub 2B and engages the teeth 46 on the drum 155. Since the drum 45 is rotating in the opposite direction, due to the fixed axes of the reserve gears 42, the reverse movement will be imparted to the driven shaft.

The clutch in which the clutch disc 30 is embodied is not used for starting or stopping purposes. It is installed simply to provide a noload idling position for the engine by disconnesting the clutch sleeve 29 from the gear housing i8.

It is desired to call attention to the fact that, when the clutch member 25 is slid to the left, it will engage the teeth d5 on the reverse drum 45 before it releases the teeth on the hub 24, so that there is no neutral or unlocked position. The shift is made, of course, when both members are stationary.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, Within the scope of the appendedvclaims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

1. An automatic fluid transmission comprising: a drive shaft; a sun gear fixed on said drive shaft; a planet gear support rotatably mounted on said drive shaft; a set of planet gears carried by said support in mesh with said drive gear; a ring gear in mesh with said planet gears; a fluid clutch transmitting rotation from said engine shaft to said ring gear; a sun gear driven by said support; a second planet gear support rotatable about the axis of said drive shaft; a second set of planet gears mounted on said second support in mesh with said sun gear; a second ring gear in mesh with said second set of planet gears, said gear; a driven shaft; and means for communieating the revolutions of said second support to said driven shaft.

2. In a hydraulic power transmitting device, the combination with an engine shaft and a driven shaft, of a drive shaft splined in the extremity of the engine shaft so as to rotate in unison therewith; a drive gear keyed to said drive shaft; a first set of planet gears in mesh with and surrounding said drive gear; a first planet gear spider rotatably mounted on said drive shaft and supporting said first set of planet gears; a hub projecting from said first spider; a sun gear fixed to said hub; a second set of planet gears in mesh with and surrounding said sun gear; a second planet gear spider rotatably mounted on said drive shaft and supporting said second set of planet gears; a second hub projecting from said second spider over the driven shaft; means for connecting said second .hub to the driven shaft; a ring gear housing rotatably mounted about both sets of planet gears; a first ring gear fixed in said housing in mesh with said first set of planet gears; a second ring gear fixed in said housing in mesh with the second set of planet gears; and a fluid power transmission device interposed between said drive shaft and said housing for rotating the latter from the former.

3. In a. hydrauliepower transmitting device, the combination with an engine shaft and a driven shaft, of a drive shaft splined in the extremity of the engine shaft so as to rotate in unison therewith; a drive gear keyed to said drive shaft; e. first set of planet gears in mesh with and surrounding said drive gear; a first planet gear spider rotatably mounted on said drive shaft and supporting said first set of planet gears; a hub projecting from said first spider; a sun gear iixed to said hub; a second set of planet gears in mesh with and surrounding said sun gear; a second planet gear spider rotatably mounted on said drive shaft and supporting said second set of planet gears; a second hub projecting from said second spider over the driven shaft; means for connecting said second hub to the driven shaft; a ring gear housing rotatably mounted about both sets of planet gears; a first ring gear fixed in said housing in mesh with said first set of planet gears; a, second ring gear xed in said housing in mesh with the second set of planet gears; a clutch sleeve rotatably surrounding said drive shaft and extending from a point within said housing to a point adjacent the splined extremity of said drive shaft; a clutch disc operated means for clutching said housing to said disc to cause the former to rotate with the latter; and a iiuid power transmission device interposed between said drive shaft and said sleeve for rotating the latter at variable speeds from the former.

4. In a hydraulic power transmitting device, the combination with an engine shaft and a driven shaft, of a drive shaft splined in the extremity of the engine shaft so as to rotate in unison therewith; a drive gear keyed to said drive shaft; a. first set of planet gears in mesh with and surrounding said drive gear; a, first planet gear spider rotatably mounted on said drive shaft and supporting said first set of planet gears; a hub projecting from said first spider; a sun gear fixed to said hub; a second set of planet gears in mesh with and surrounding said sun gear; a second planet gear spider rotatably mounted on said drive shaft and supporting said second set of second ring gear being fixed to said first ring 1| planet gears; a second hub projecting from said 5 second spider over the driven shaft; means for REFERENCES CITED connecting saidgsecond hub to the driven shaft; a. ring gear housing rotatably mounted about The following references are of record in the both sets of planet gears; a first ring gear fixed file of this paient! in said housing in mesh with said lrst set of planet gears; a second ring gear fixed in said UNTIED STATES PATENTS housing in mesh with the second set of planet gears; a clutch sleeve rotatably surrounding said Nlggeiie Blygg'e Maynzagelgm drive shaft and extending from a point within 1203265 Radcliff-e Oct 31' 1916 said housing to a point adjacent the splined ex 10 2312849 Pollard Ma, 2 1943 tremity of said drive shaft; a clutch disc mounted 2391333 Nardme Dec '18 1945 on said sleeve within said housing; manually operated means for clutching said housing to said disc to cause the former to rotate with the latter; FOREIGN PATENTS a bladed uid clutch rotor fixed to said clutch Number Country Date sleeve adjacent the spiined extremity of said 379,973 Great Britain Sept. 8, 1932 drive shaft; and a, fluid containing housing fixed 384,816 Great Britain Dec. 15, 1932 to the engine shaft and surrounding said rotor for imparting variable rotation from said engine shaft to said rotor. 20

ROBERT F. GREBB. 

